In some electrophotographic systems having organic photoconductor elements, a loss of resolution in print quality occurs over the desired period of use because of a modification of the outer surface of the photosensitive element. In dry electrophotographic systems the surface of a photoconductor tends to become contaminated with materials that reduce the performance of the photoconductor and limit its useful life. The life of such a photoconductor is extended by providing an abrasive toner mix which causes the surface of the photoconductor to slowly abrade away over the intended period of use. This abrasion process cleans the photoconductor surface and keeps the surface fresh. Japanese patent application 1196072 published Aug. 7, 1994, assigned to Canon Corp., is understood to be directed to such intentional abrasion in a dry toning system.
In liquid toning electrophotographic systems the carrier fluid is typically an oil which lubricates the surface and provides a protective film which decreases the amount of abrasion that the photoconductor experiences in the imaging process. Also, since the electrophotographic process requires the use of elevated temperatures to assist in transferring the toner from the photoconductor, the photoconductor must have a high glass transition temperature (Tg) in order to function properly. The high Tg results in organic photconductive materials which are more rigid and inflexible, and therefore have more resistance to abrasion. Similarly, a photoconductor subject to liquid developer must have resistance to the solvent action of the developer.
U.S. Pat. No. 4,420,244 to Landa employs a liquid toner in which hard particles are included in the toner as spacers. Abrasion from these particles is recognized and is considered undesirable.